matrix manipulation : ind of wanted rows and columns stocked in a vector

Dear all, for a square matrix is it possible to get only the the first and the third (not the second) rows and columns : the wanted are stocked in a B vector

A = 
          35     6    19
           3     7    23
          31     2    27
  B = (1 3)
  C = function (A, B)
  C = 
            35     19
            31     27

Answer 1

[David Goodmanson]

Hi Lila, you just have to make an index vector:

B = [1 3];
C = A(B,B)

The row index is the first listed and the column index is second, and these can be independent:

>> A = magic(5)

A = 17    24     1     8    15
    23     5     7    14    16
     4     6    13    20    22
    10    12    19    21     3
    11    18    25     2     9

>> C = A([1 3 4],[3 5])

C =  1    15
    13    22
    19     3